
  body {
  /* display: flex; */
  flex-direction: column;
  /* align-items: center; 水平居中 */
  background: #f9f9f9;
  /* padding: 20px; */
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}
.main_body{
    display: flex;
  flex-direction: column;
  align-items: center; /* 水平居中 */
  background: #f9f9f9;
  padding: 20px;
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}
.video-container {
  width: 100%;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  max-width: 900px;

  margin: 0 auto; /* 水平居中 */
}

video,.courseVideo  {
  width: 100%;
  border-radius: 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.discussion-container {
  max-width: 900px;
  width: 100%;
  margin: 20px auto 0; /* 水平居中并与上面有间距 */
  background: white;
  border-radius: 8px;
  padding: 15px 20px;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

  .discussion-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 10px;
    border-bottom: 2px solid #1890ff;
    padding-bottom: 6px;
  }
  .comments-list {
    max-height: 300px;
    overflow-y: auto;
    margin-bottom: 15px;
  }
  .comment-item {
    border-bottom: 1px solid #eee;
    padding: 10px 0;
  }
  .comment-item:last-child {
    border-bottom: none;
  }
  .comment-user {
    font-weight: 600;
    color: #1890ff;
    margin-bottom: 4px;
  }
  .comment-text {
    line-height: 1.4;
    color: #333;
  }
  .add-comment {
    display: flex;
    gap: 10px;
  }
  .add-comment textarea {
    flex-grow: 1;
    padding: 8px 10px;
    font-size: 1rem;
    border: 1px solid #ccc;
    border-radius: 6px;
    resize: none;
    min-height: 50px;
  }
  .add-comment button {
    background-color: #1890ff;
    border: none;
    color: white;
    padding: 0 20px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s ease;
  }
  .add-comment button:hover {
    background-color: #40a9ff;
  }
